

// 定义 AbstractHmmParams trait
pub trait AbstractHmmParams {
    fn start(&self, state: &str) -> f64;
    fn emission(&self, state: &str, observation: &str) -> f64;
    fn transition(&self, from_state: &str, to_state: &str) -> f64;
    fn get_states(&self, observation: &str) -> Vec<String>;
}